The partial purification of the thymic hormone thymosin has been described by Goldstein et al., Proc. Nat. Acad. Sci. (U.S.A.) 56, 1010-1017 (1966).
An even cruder form of thymosin and a method for its preparation is described in French Medicinal Pat. No. 7,373 delivered Oct. 27, 1969, which claims priority from U.S. Pat. Application Ser. No. 580,558, filed Aug. 24, 1966, inventors Abraham White and Allan L. Goldstein, now abandoned.
Thymosin fraction 5 which has been widely employed recently in the biological investigations of thymosin is known to contain at least 12 heat-stable acidic peptides and proteins with molecular weights that range from 1,200 to 14,000.
More recently Goldstein et al., Proc. Nat. Acad. Sci. (U.S.A.) 69, 1800-1803 (1972) described an improved purification procedure for thymosin. It is believed that the material obtained by this process which is indicated to be homogeneous, in fact comprises at least three separate components when examined electrophoretically on 15% polyacrylamide gel.
Thus thymosin materials previously available in the art have all been non-homogeneous preparations and therefore not suited for use in chemical structure elucidation studies which are necessary before chemical approaches leading to the synthetic preparation of this biologically valuable hormone can be achieved. In addition homogeneous thymosin preparations are valuable as starting materials in preparing highly specific antibodies to thymosin which in turn are the basis for sensitive and efficient immunoassays for this hormone.